Crop cover and rotations for an agriculture in forced expansion

Current agriculture faces the challenge of increasing the production of a growing demand, and at the same time avoiding an unaffordable environmental cost for future generations. By definition, agriculture is not sustainable, but we can use the knowledge accumulated over centuries, science, and technology to mitigate the negative effects of its impact. One of the most promising approaches to improve this ‘sustainability’ is promoting the biodiversity of agricultural fields, both crops and soil microorganisms.

 

For this we need crop rotations. They are necessary to diversify herbicides and thus avoid resistant weeds that reduce crop yield. One strategy is to alternate ‘broadleaf’ and ‘grass’ crops, as different herbicides are used. On the other hand, in the rotations, different crop traits can be used to favour the establishment and production of those that follow them. For example:

 

Oilseeds (e.g., sunflower or rapeseed), whose pivot roots allow them to go deep into the soil and ‘till’ it, thus improving soil structure.

 

Cereals (e.g., wheat, barley, oats), which are more demanding in terms of resources, but currently the varieties are high yielding. They take advantage of the enrichment in organic matter of the sunflower or rapeseed, and water is not usually a problem.

 

Legumes (e.g., peas, soybeans), which enrich the soil in nitrogen, the most important element for plants after water.

If the region is not ‘water-stressed’, then growing maize is a good option. The soil has been enriched in nitrogen and organic matter from previous harvests.

 

 

Rotational trio outside Gatersleben, Germany.

 

 In addition, it was recently published in Nature that using crop cover (the vegetation that covers agricultural field, be it a crop or another plant species), is even more effective than rotations for soil integrity and cereal production in Europe, this is, for soil fertility. The results of this study suggest the importance of extending the duration of the crop cover beyond the limitations imposed by the climatic conditions of the specific area. For example, use them also between the time interval after harvest and the establishment of the next crop.

 

However, in the current situation of gas and grain shortages due to the war in Ukraine, the German authorities are ‘lobbying’ EU to eliminate rules regarding rotations and thus cede more hectares and dedication not only to cereals but to maize crops to provide bioenergy. It makes it clear that pursuing profit in aeternum is, and has always been, the priority at any cost, and that without gas, oil or a strong agricultural business it is difficult to achieve.